/* -*- mode: C; c-basic-offset: 4 -*- */
#ident "Copyright (c) 2007, 2008 Tokutek Inc. All rights reserved."
#include "includes.h"
// execute the cachetable callbacks using a writer thread 0->no 1->yes
#define DO_WRITER_THREAD 1
#if DO_WRITER_THREAD
static void *cachetable_writer(void *);
#endif
// we use 4 threads since gunzip is 4 times faster than gzip
#define MAX_WRITER_THREADS 4
// use cachetable locks 0->no 1->yes
#define DO_CACHETABLE_LOCK 1
// unlock the cachetable while executing callbacks 0->no 1->yes
#define DO_CALLBACK_UNLOCK 1
// simulate long latency write operations with usleep. time in milliseconds.
#define DO_CALLBACK_USLEEP 0
#define DO_CALLBACK_BUSYWAIT 0
//#define TRACE_CACHETABLE
#ifdef TRACE_CACHETABLE
#define WHEN_TRACE_CT(x) x
#else
#define WHEN_TRACE_CT(x) ((void)0)
#endif
typedef struct ctpair *PAIR;
struct ctpair {
enum typ_tag tag;
char dirty;
char verify_flag; // Used in verify_cachetable()
char writing; // writing back
char write_me;
CACHEKEY key;
void *value;
long size;
PAIR next,prev; // In LRU list.
PAIR hash_chain;
CACHEFILE cachefile;
CACHETABLE_FLUSH_CALLBACK flush_callback;
CACHETABLE_FETCH_CALLBACK fetch_callback;
void *extraargs;
LSN modified_lsn; // What was the LSN when modified (undefined if not dirty)
LSN written_lsn; // What was the LSN when written (we need to get this information when we fetch)
u_int32_t fullhash;
PAIR next_wq; // the ctpair's are linked into a write queue when evicted
struct ctpair_rwlock rwlock; // reader writer lock used to grant an exclusive lock to the writeback thread
struct writequeue *cq; // writers sometimes return ctpair's using this queue
};
#include "cachetable-writequeue.h"
static inline void ctpair_destroy(PAIR p) {
ctpair_rwlock_destroy(&p->rwlock);
toku_free(p);
}
// The cachetable is as close to an ENV as we get.
struct cachetable {
enum typ_tag tag;
u_int32_t n_in_table;
u_int32_t table_size;
PAIR *table; // hash table
PAIR head,tail; // of LRU list. head is the most recently used. tail is least recently used.
CACHEFILE cachefiles; // list of cachefiles that use this cachetable
long size_current; // the sum of the sizes of the pairs in the cachetable
long size_limit; // the limit to the sum of the pair sizes
long size_writing; // the sum of the sizes of the pairs being written
LSN lsn_of_checkpoint; // the most recent checkpoint in the log.
TOKULOGGER logger;
toku_pthread_mutex_t mutex; // coarse lock that protects the cachetable, the cachefiles, and the pair's
struct writequeue wq; // write queue for the writer threads
THREADPOOL threadpool; // pool of writer threads
char checkpointing; // checkpoint in progress
};
// lock the cachetable mutex
static inline void cachetable_lock(CACHETABLE ct __attribute__((unused))) {
#if DO_CACHETABLE_LOCK
int r = toku_pthread_mutex_lock(&ct->mutex); assert(r == 0);
#endif
}
// unlock the cachetable mutex
static inline void cachetable_unlock(CACHETABLE ct __attribute__((unused))) {
#if DO_CACHETABLE_LOCK
int r = toku_pthread_mutex_unlock(&ct->mutex); assert(r == 0);
#endif
}
// wait for writes to complete if the size in the write queue is 1/2 of
// the cachetable
static inline void cachetable_wait_write(CACHETABLE ct) {
while (2*ct->size_writing > ct->size_current) {
writequeue_wait_write(&ct->wq, &ct->mutex);
}
}
struct cachefile {
CACHEFILE next;
u_int64_t refcount; /* CACHEFILEs are shared. Use a refcount to decide when to really close it.
* The reference count is one for every open DB.
* Plus one for every commit/rollback record. (It would be harder to keep a count for every open transaction,
* because then we'd have to figure out if the transaction was already counted. If we simply use a count for
* every record in the transaction, we'll be ok. Hence we use a 64-bit counter to make sure we don't run out.
*/
int fd; /* Bug: If a file is opened read-only, then it is stuck in read-only. If it is opened read-write, then subsequent writers can write to it too. */
CACHETABLE cachetable;
struct fileid fileid;
FILENUM filenum;
char *fname;
void *userdata;
int (*close_userdata)(CACHEFILE cf, void *userdata); // when closing the last reference to a cachefile, first call this function.
int (*checkpoint_userdata)(CACHEFILE cf, void *userdata); // when checkpointing a cachefile, call this function.
};
int toku_create_cachetable(CACHETABLE *result, long size_limit, LSN initial_lsn, TOKULOGGER logger) {
#if defined __linux__
{
static int did_mallopt = 0;
if (!did_mallopt) {
mallopt(M_MMAP_THRESHOLD, 1024*64); // 64K and larger should be malloced with mmap().
did_mallopt = 1;
}
}
#endif
TAGMALLOC(CACHETABLE, t);
if (t == 0) return ENOMEM;
t->n_in_table = 0;
t->table_size = 4;
MALLOC_N(t->table_size, t->table);
assert(t->table);
t->head = t->tail = 0;
u_int32_t i;
for (i=0; i<t->table_size; i++) {
t->table[i]=0;
}
t->cachefiles = 0;
t->size_current = 0;
t->size_limit = size_limit;
t->size_writing = 0;
t->lsn_of_checkpoint = initial_lsn;
t->logger = logger;
t->checkpointing = 0;
int r;
writequeue_init(&t->wq);
r = toku_pthread_mutex_init(&t->mutex, 0); assert(r == 0);
// set the max number of writeback threads to min(MAX_WRITER_THREADS,nprocs_online)
int nprocs = toku_os_get_number_active_processors();
if (nprocs > MAX_WRITER_THREADS) nprocs = MAX_WRITER_THREADS;
r = threadpool_create(&t->threadpool, nprocs); assert(r == 0);
#if DO_WRITER_THREAD
threadpool_maybe_add(t->threadpool, cachetable_writer, t);
#endif
*result = t;
return 0;
}
// What cachefile goes with particular fd?
int toku_cachefile_of_filenum (CACHETABLE t, FILENUM filenum, CACHEFILE *cf) {
CACHEFILE extant;
for (extant = t->cachefiles; extant; extant=extant->next) {
if (extant->filenum.fileid==filenum.fileid) {
*cf = extant;
return 0;
}
}
return ENOENT;
}
static FILENUM next_filenum_to_use={0};
static void cachefile_init_filenum(CACHEFILE newcf, int fd, const char *fname, struct fileid fileid) \
{
newcf->fd = fd;
newcf->fileid = fileid;
newcf->fname = fname ? toku_strdup(fname) : 0;
}
// If something goes wrong, close the fd. After this, the caller shouldn't close the fd, but instead should close the cachefile.
int toku_cachetable_openfd (CACHEFILE *cf, CACHETABLE t, int fd, const char *fname) {
int r;
CACHEFILE extant;
struct fileid fileid;
r = toku_os_get_unique_file_id(fd, &fileid);
if (r != 0) {
r=errno; close(fd);
return r;
}
for (extant = t->cachefiles; extant; extant=extant->next) {
if (memcmp(&extant->fileid, &fileid, sizeof(fileid))==0) {
r = close(fd);
assert(r == 0);
extant->refcount++;
*cf = extant;
return 0;
}
}
try_again:
for (extant = t->cachefiles; extant; extant=extant->next) {
if (next_filenum_to_use.fileid==extant->filenum.fileid) {
next_filenum_to_use.fileid++;
goto try_again;
}
}
{
CACHEFILE MALLOC(newcf);
newcf->cachetable = t;
newcf->filenum.fileid = next_filenum_to_use.fileid++;
cachefile_init_filenum(newcf, fd, fname, fileid);
newcf->refcount = 1;
newcf->next = t->cachefiles;
t->cachefiles = newcf;
newcf->userdata = 0;
newcf->close_userdata = 0;
newcf->checkpoint_userdata = 0;
*cf = newcf;
return 0;
}
}
int toku_cachetable_openf (CACHEFILE *cf, CACHETABLE t, const char *fname, int flags, mode_t mode) {
int fd = open(fname, flags+O_BINARY, mode);
if (fd<0) return errno;
return toku_cachetable_openfd (cf, t, fd, fname);
}
int toku_cachefile_set_fd (CACHEFILE cf, int fd, const char *fname) {
int r;
struct fileid fileid;
r=toku_os_get_unique_file_id(fd, &fileid);
if (r != 0) {
r=errno; close(fd); return r;
}
if (cf->close_userdata && (r = cf->close_userdata(cf, cf->userdata))) {
return r;
}
cf->close_userdata = NULL;
cf->checkpoint_userdata = NULL;
cf->userdata = NULL;
close(cf->fd);
cf->fd = -1;
if (cf->fname) {
toku_free(cf->fname);
cf->fname = 0;
}
cachefile_init_filenum(cf, fd, fname, fileid);
return 0;
}
int toku_cachefile_fd (CACHEFILE cf) {
return cf->fd;
}
int toku_cachefile_truncate0 (CACHEFILE cf) {
int r = ftruncate(cf->fd, 0);
if (r != 0)
r = errno;
return r;
}
static CACHEFILE remove_cf_from_list (CACHEFILE cf, CACHEFILE list) {
if (list==0) return 0;
else if (list==cf) {
return list->next;
} else {
list->next = remove_cf_from_list(cf, list->next);
return list;
}
}
static int cachefile_write_maybe_remove (CACHETABLE, CACHEFILE cf, BOOL do_remove);
// Increment the reference count
void toku_cachefile_refup (CACHEFILE cf) {
cf->refcount++;
}
int toku_cachefile_close (CACHEFILE *cfp, TOKULOGGER logger) {
CACHEFILE cf = *cfp;
CACHETABLE ct = cf->cachetable;
cachetable_lock(ct);
assert(cf->refcount>0);
cf->refcount--;
if (cf->refcount==0) {
int r;
if ((r = cachefile_write_maybe_remove(ct, cf, TRUE))) {
cachetable_unlock(ct);
return r;
}
if (cf->close_userdata && (r = cf->close_userdata(cf, cf->userdata))) {
cachetable_unlock(ct);
return r;
}
cf->close_userdata = NULL;
cf->checkpoint_userdata = NULL;
cf->userdata = NULL;
cf->cachetable->cachefiles = remove_cf_from_list(cf, cf->cachetable->cachefiles);
cachetable_unlock(ct);
r = close(cf->fd);
assert(r == 0);
cf->fd = -1;
if (logger) {
//assert(cf->fname);
//BYTESTRING bs = {.len=strlen(cf->fname), .data=cf->fname};
//r = toku_log_cfclose(logger, 0, 0, bs, cf->filenum);
}
if (cf->fname)
toku_free(cf->fname);
toku_free(cf);
*cfp=0;
return r;
} else {
cachetable_unlock(ct);
*cfp=0;
return 0;
}
}
int toku_cachefile_flush (CACHEFILE cf) {
CACHETABLE ct = cf->cachetable;
cachetable_lock(ct);
int r = cachefile_write_maybe_remove(ct, cf, TRUE);
cachetable_unlock(ct);
return r;
}
// This hash function comes from Jenkins: http://burtleburtle.net/bob/c/lookup3.c
// The idea here is to mix the bits thoroughly so that we don't have to do modulo by a prime number.
// Instead we can use a bitmask on a table of size power of two.
// This hash function does yield improved performance on ./db-benchmark-test-tokudb and ./scanscan
static inline u_int32_t rot(u_int32_t x, u_int32_t k) {
return (x<<k) | (x>>(32-k));
}
static inline u_int32_t final (u_int32_t a, u_int32_t b, u_int32_t c) {
c ^= b; c -= rot(b,14);
a ^= c; a -= rot(c,11);
b ^= a; b -= rot(a,25);
c ^= b; c -= rot(b,16);
a ^= c; a -= rot(c,4);
b ^= a; b -= rot(a,14);
c ^= b; c -= rot(b,24);
return c;
}
u_int32_t toku_cachetable_hash (CACHEFILE cachefile, BLOCKNUM key)
// Effect: Return a 32-bit hash key. The hash key shall be suitable for using with bitmasking for a table of size power-of-two.
{
return final(cachefile->filenum.fileid, (u_int32_t)(key.b>>32), (u_int32_t)key.b);
}
#if 0
static unsigned int hashit (CACHETABLE t, CACHEKEY key, CACHEFILE cachefile) {
assert(0==(t->table_size & (t->table_size -1))); // make sure table is power of two
return (toku_cachetable_hash(key,cachefile))&(t->table_size-1);
}
#endif
static void cachetable_rehash (CACHETABLE t, u_int32_t newtable_size) {
// printf("rehash %p %d %d %d\n", t, primeindexdelta, t->n_in_table, t->table_size);
assert(newtable_size>=4 && ((newtable_size & (newtable_size-1))==0));
PAIR *newtable = toku_calloc(newtable_size, sizeof(*t->table));
u_int32_t i;
//printf("%s:%d newtable_size=%d\n", __FILE__, __LINE__, newtable_size);
assert(newtable!=0);
u_int32_t oldtable_size = t->table_size;
t->table_size=newtable_size;
for (i=0; i<newtable_size; i++) newtable[i]=0;
for (i=0; i<oldtable_size; i++) {
PAIR p;
while ((p=t->table[i])!=0) {
unsigned int h = p->fullhash&(newtable_size-1);
t->table[i] = p->hash_chain;
p->hash_chain = newtable[h];
newtable[h] = p;
}
}
toku_free(t->table);
// printf("Freed\n");
t->table=newtable;
//printf("Done growing or shrinking\n");
}
static void lru_remove (CACHETABLE t, PAIR p) {
if (p->next) {
p->next->prev = p->prev;
} else {
assert(t->tail==p);
t->tail = p->prev;
}
if (p->prev) {
p->prev->next = p->next;
} else {
assert(t->head==p);
t->head = p->next;
}
p->prev = p->next = 0;
}
static void lru_add_to_list (CACHETABLE t, PAIR p) {
// requires that touch_me is not currently in the table.
assert(p->prev==0);
p->prev = 0;
p->next = t->head;
if (t->head) {
t->head->prev = p;
} else {
assert(!t->tail);
t->tail = p;
}
t->head = p;
}
static void lru_touch (CACHETABLE t, PAIR p) {
lru_remove(t,p);
lru_add_to_list(t,p);
}
static PAIR remove_from_hash_chain (PAIR remove_me, PAIR list) {
if (remove_me==list) return list->hash_chain;
list->hash_chain = remove_from_hash_chain(remove_me, list->hash_chain);
return list;
}
// Predicate to determine if a node must be renamed. Nodes are renamed on the time they are written
// after a checkpoint.
// Thus we need to rename it if it is dirty,
// if it has been modified within the current checkpoint regime (hence non-strict inequality)
// and the last time it was written was in a previous checkpoint regime (strict inequality)
static BOOL need_to_rename_p (CACHETABLE t, PAIR p) {
return (BOOL)(p->dirty
&& p->modified_lsn.lsn>=t->lsn_of_checkpoint.lsn // nonstrict
&& p->written_lsn.lsn < t->lsn_of_checkpoint.lsn); // strict
}
// Remove a pair from the cachetable
// Effects: the pair is removed from the LRU list and from the cachetable's hash table.
// The size of the objects in the cachetable is adjusted by the size of the pair being
// removed.
static void cachetable_remove_pair (CACHETABLE ct, PAIR p) {
lru_remove(ct, p);
assert(ct->n_in_table>0);
ct->n_in_table--;
// Remove it from the hash chain.
{
unsigned int h = p->fullhash&(ct->table_size-1);
ct->table[h] = remove_from_hash_chain (p, ct->table[h]);
}
ct->size_current -= p->size; assert(ct->size_current >= 0);
}
// Maybe remove a pair from the cachetable and free it, depending on whether
// or not there are any threads interested in the pair. The flush callback
// is called with write_me and keep_me both false, and the pair is destroyed.
static void cachetable_maybe_remove_and_free_pair (CACHETABLE ct, PAIR p) {
if (ctpair_users(&p->rwlock) == 0) {
cachetable_remove_pair(ct, p);
#if DO_CALLBACK_UNLOCK
cachetable_unlock(ct);
#endif
p->flush_callback(p->cachefile, p->key, p->value, p->extraargs, p->size, FALSE, FALSE,
ct->lsn_of_checkpoint, need_to_rename_p(ct, p));
ctpair_destroy(p);
#if DO_CALLBACK_UNLOCK
cachetable_lock(ct);
#endif
}
}
static void cachetable_complete_write_pair (CACHETABLE ct, PAIR p, BOOL do_remove);
// Write a pair to storage
// Effects: an exclusive lock on the pair is obtained, the write callback is called,
// the pair dirty state is adjusted, and the write is completed. The write_me boolean
// is true when the pair is dirty and the pair is requested to be written. The keep_me
// boolean is true, so the pair is not yet evicted from the cachetable.
static void cachetable_write_pair(CACHETABLE ct, PAIR p) {
ctpair_write_lock(&p->rwlock, &ct->mutex);
#if DO_CALLBACK_UNLOCK
cachetable_unlock(ct);
#endif
// write callback
p->flush_callback(p->cachefile, p->key, p->value, p->extraargs, p->size, (BOOL)(p->dirty && p->write_me), TRUE,
ct->lsn_of_checkpoint, need_to_rename_p(ct, p));
#if DO_CALLBACK_USLEEP
usleep(DO_CALLBACK_USLEEP);
#endif
#if DO_CALLBACK_BUSYWAIT
struct timeval tstart;
gettimeofday(&tstart, 0);
long long ltstart = tstart.tv_sec * 1000000 + tstart.tv_usec;
while (1) {
struct timeval t;
gettimeofday(&t, 0);
long long lt = t.tv_sec * 1000000 + t.tv_usec;
if (lt - ltstart > DO_CALLBACK_BUSYWAIT)
break;
}
#endif
#if DO_CALLBACK_UNLOCK
cachetable_lock(ct);
#endif
// the pair is no longer dirty once written
if (p->dirty && p->write_me)
p->dirty = FALSE;
// stuff it into a completion queue for delayed completion if a completion queue exists
// otherwise complete the write now
if (p->cq)
writequeue_enq(p->cq, p);
else
cachetable_complete_write_pair(ct, p, TRUE);
}
// complete the write of a pair by reseting the writing flag, adjusting the write
// pending size, and maybe removing the pair from the cachetable if there are no
// references to it
static void cachetable_complete_write_pair (CACHETABLE ct, PAIR p, BOOL do_remove) {
p->cq = 0;
p->writing = 0;
// maybe wakeup any stalled writers when the pending writes fall below
// 1/8 of the size of the cachetable
ct->size_writing -= p->size;
assert(ct->size_writing >= 0);
if (8*ct->size_writing <= ct->size_current)
writequeue_wakeup_write(&ct->wq);
ctpair_write_unlock(&p->rwlock);
if (do_remove)
cachetable_maybe_remove_and_free_pair(ct, p);
}
// flush and remove a pair from the cachetable. the callbacks are run by a thread in
// a thread pool.
static void flush_and_remove (CACHETABLE ct, PAIR p, int write_me) {
p->writing = 1;
ct->size_writing += p->size; assert(ct->size_writing >= 0);
p->write_me = (char)(write_me?1:0);
#if DO_WRITER_THREAD
if (!p->dirty || !p->write_me) {
// evictions without a write can be run in the current thread
cachetable_write_pair(ct, p);
} else {
threadpool_maybe_add(ct->threadpool, cachetable_writer, ct);
writequeue_enq(&ct->wq, p);
}
#else
cachetable_write_pair(ct, p);
#endif
}
static int maybe_flush_some (CACHETABLE t, long size) {
int r = 0;
again:
if (size + t->size_current > t->size_limit + t->size_writing) {
{
//unsigned long rss __attribute__((__unused__)) = check_max_rss();
//printf("this-size=%.6fMB projected size = %.2fMB limit=%2.fMB rss=%2.fMB\n", size/(1024.0*1024.0), (size+t->size_current)/(1024.0*1024.0), t->size_limit/(1024.0*1024.0), rss/256.0);
//struct mallinfo m = mallinfo();
//printf(" arena=%d hblks=%d hblkhd=%d\n", m.arena, m.hblks, m.hblkhd);
}
/* Try to remove one. */
PAIR remove_me;
for (remove_me = t->tail; remove_me; remove_me = remove_me->prev) {
if (!ctpair_users(&remove_me->rwlock) && !remove_me->writing) {
flush_and_remove(t, remove_me, 1);
goto again;
}
}
/* All were pinned. */
//printf("All are pinned\n");
return 0; // Don't indicate an error code. Instead let memory get overfull.
}
if ((4 * t->n_in_table < t->table_size) && t->table_size > 4)
cachetable_rehash(t, t->table_size/2);
return r;
}
static int cachetable_insert_at(CACHEFILE cachefile, u_int32_t fullhash, CACHEKEY key, void *value, long size,
CACHETABLE_FLUSH_CALLBACK flush_callback,
CACHETABLE_FETCH_CALLBACK fetch_callback,
void *extraargs, int dirty,
LSN written_lsn) {
TAGMALLOC(PAIR, p);
memset(p, 0, sizeof *p);
ctpair_rwlock_init(&p->rwlock);
p->fullhash = fullhash;
p->dirty = (char)(dirty ? 1 : 0); //printf("%s:%d p=%p dirty=%d\n", __FILE__, __LINE__, p, p->dirty);
p->size = size;
p->writing = 0;
p->key = key;
p->value = value;
p->next = p->prev = 0;
p->cachefile = cachefile;
p->flush_callback = flush_callback;
p->fetch_callback = fetch_callback;
p->extraargs = extraargs;
p->modified_lsn.lsn = 0;
p->written_lsn = written_lsn;
p->fullhash = fullhash;
CACHETABLE ct = cachefile->cachetable;
ctpair_read_lock(&p->rwlock, &ct->mutex);
p->cq = 0;
lru_add_to_list(ct, p);
u_int32_t h = fullhash & (ct->table_size-1);
p->hash_chain = ct->table[h];
ct->table[h] = p;
ct->n_in_table++;
ct->size_current += size;
if (ct->n_in_table > ct->table_size) {
cachetable_rehash(ct, ct->table_size*2);
}
return 0;
}
enum { hash_histogram_max = 100 };
static unsigned long long hash_histogram[hash_histogram_max];
void print_hash_histogram (void) {
int i;
for (i=0; i<hash_histogram_max; i++)
if (hash_histogram[i]) printf("%d:%llu ", i, hash_histogram[i]);
printf("\n");
}
static void
note_hash_count (int count) {
if (count>=hash_histogram_max) count=hash_histogram_max-1;
hash_histogram[count]++;
}
int toku_cachetable_put(CACHEFILE cachefile, CACHEKEY key, u_int32_t fullhash, void*value, long size,
CACHETABLE_FLUSH_CALLBACK flush_callback,
CACHETABLE_FETCH_CALLBACK fetch_callback, void *extraargs) {
WHEN_TRACE_CT(printf("%s:%d CT cachetable_put(%lld)=%p\n", __FILE__, __LINE__, key, value));
CACHETABLE ct = cachefile->cachetable;
int count=0;
cachetable_lock(ct);
cachetable_wait_write(ct);
{
PAIR p;
for (p=ct->table[fullhash&(cachefile->cachetable->table_size-1)]; p; p=p->hash_chain) {
count++;
if (p->key.b==key.b && p->cachefile==cachefile) {
// Semantically, these two asserts are not strictly right. After all, when are two functions eq?
// In practice, the functions better be the same.
assert(p->flush_callback==flush_callback);
assert(p->fetch_callback==fetch_callback);
ctpair_read_lock(&p->rwlock, &ct->mutex);
cachetable_unlock(ct);
note_hash_count(count);
return -1; /* Already present. */
}
}
}
int r;
if ((r=maybe_flush_some(ct, size))) {
cachetable_unlock(ct);
return r;
}
// flushing could change the table size, but wont' change the fullhash
r = cachetable_insert_at(cachefile, fullhash, key, value, size, flush_callback, fetch_callback, extraargs, 1, ZERO_LSN);
cachetable_unlock(ct);
note_hash_count(count);
return r;
}
int toku_cachetable_get_and_pin(CACHEFILE cachefile, CACHEKEY key, u_int32_t fullhash, void**value, long *sizep,
CACHETABLE_FLUSH_CALLBACK flush_callback,
CACHETABLE_FETCH_CALLBACK fetch_callback, void *extraargs) {
CACHETABLE t = cachefile->cachetable;
PAIR p;
int count=0;
cachetable_lock(t);
cachetable_wait_write(t);
for (p=t->table[fullhash&(t->table_size-1)]; p; p=p->hash_chain) {
count++;
if (p->key.b==key.b && p->cachefile==cachefile) {
*value = p->value;
if (sizep) *sizep = p->size;
ctpair_read_lock(&p->rwlock, &t->mutex);
lru_touch(t,p);
cachetable_unlock(t);
note_hash_count(count);
WHEN_TRACE_CT(printf("%s:%d cachtable_get_and_pin(%lld)--> %p\n", __FILE__, __LINE__, key, *value));
return 0;
}
}
note_hash_count(count);
int r;
// Note. hashit(t,key) may have changed as a result of flushing. But fullhash won't have changed.
{
void *toku_value;
long size = 1; // compat
LSN written_lsn;
WHEN_TRACE_CT(printf("%s:%d CT: fetch_callback(%lld...)\n", __FILE__, __LINE__, key));
if ((r=fetch_callback(cachefile, key, fullhash, &toku_value, &size, extraargs, &written_lsn))) {
if (r == DB_BADFORMAT) toku_db_badformat();
cachetable_unlock(t);
return r;
}
cachetable_insert_at(cachefile, fullhash, key, toku_value, size, flush_callback, fetch_callback, extraargs, 0, written_lsn);
*value = toku_value;
if (sizep)
*sizep = size;
}
r = maybe_flush_some(t, 0);
if (r == DB_BADFORMAT) toku_db_badformat();
cachetable_unlock(t);
WHEN_TRACE_CT(printf("%s:%d did fetch: cachtable_get_and_pin(%lld)--> %p\n", __FILE__, __LINE__, key, *value));
return r;
}
// Lookup a key in the cachetable. If it is found and it is not being written, then
// acquire a read lock on the pair, update the LRU list, and return sucess. However,
// if it is being written, then allow the writer to evict it. This prevents writers
// being suspended on a block that was just selected for eviction.
int toku_cachetable_maybe_get_and_pin (CACHEFILE cachefile, CACHEKEY key, u_int32_t fullhash, void**value) {
CACHETABLE t = cachefile->cachetable;
PAIR p;
int count = 0;
cachetable_lock(t);
for (p=t->table[fullhash&(t->table_size-1)]; p; p=p->hash_chain) {
count++;
if (p->key.b==key.b && p->cachefile==cachefile && !p->writing) {
*value = p->value;
ctpair_read_lock(&p->rwlock, &t->mutex);
lru_touch(t,p);
cachetable_unlock(t);
note_hash_count(count);
//printf("%s:%d cachetable_maybe_get_and_pin(%lld)--> %p\n", __FILE__, __LINE__, key, *value);
return 0;
}
}
cachetable_unlock(t);
note_hash_count(count);
return -1;
}
int toku_cachetable_unpin(CACHEFILE cachefile, CACHEKEY key, u_int32_t fullhash, int dirty, long size) {
CACHETABLE t = cachefile->cachetable;
PAIR p;
WHEN_TRACE_CT(printf("%s:%d unpin(%lld)", __FILE__, __LINE__, key));
//printf("%s:%d is dirty now=%d\n", __FILE__, __LINE__, dirty);
int count = 0;
//assert(fullhash == toku_cachetable_hash(cachefile, key));
cachetable_lock(t);
for (p=t->table[fullhash&(t->table_size-1)]; p; p=p->hash_chain) {
count++;
if (p->key.b==key.b && p->cachefile==cachefile) {
assert(p->rwlock.pinned>0);
ctpair_read_unlock(&p->rwlock);
if (dirty) p->dirty = TRUE;
if (size != 0) {
t->size_current -= p->size; if (p->writing) t->size_writing -= p->size;
p->size = size;
t->size_current += p->size; if (p->writing) t->size_writing += p->size;
}
WHEN_TRACE_CT(printf("[count=%lld]\n", p->pinned));
{
int r;
if ((r=maybe_flush_some(t, 0))) {
cachetable_unlock(t);
return r;
}
}
cachetable_unlock(t);
note_hash_count(count);
return 0;
}
}
cachetable_unlock(t);
note_hash_count(count);
return -1;
}
// effect: Move an object from one key to another key.
// requires: The object is pinned in the table
int toku_cachetable_rename (CACHEFILE cachefile, CACHEKEY oldkey, CACHEKEY newkey) {
CACHETABLE t = cachefile->cachetable;
PAIR *ptr_to_p,p;
int count = 0;
u_int32_t fullhash = toku_cachetable_hash(cachefile, oldkey);
cachetable_lock(t);
for (ptr_to_p = &t->table[fullhash&(t->table_size-1)], p = *ptr_to_p;
p;
ptr_to_p = &p->hash_chain, p = *ptr_to_p) {
count++;
if (p->key.b==oldkey.b && p->cachefile==cachefile) {
note_hash_count(count);
*ptr_to_p = p->hash_chain;
p->key = newkey;
u_int32_t new_fullhash = toku_cachetable_hash(cachefile, newkey);
u_int32_t nh = new_fullhash&(t->table_size-1);
p->fullhash = new_fullhash;
p->hash_chain = t->table[nh];
t->table[nh] = p;
cachetable_unlock(t);
return 0;
}
}
cachetable_unlock(t);
note_hash_count(count);
return -1;
}
void toku_cachefile_verify (CACHEFILE cf) {
toku_cachetable_verify(cf->cachetable);
}
void toku_cachetable_verify (CACHETABLE t) {
cachetable_lock(t);
// First clear all the verify flags by going through the hash chains
{
u_int32_t i;
for (i=0; i<t->table_size; i++) {
PAIR p;
for (p=t->table[i]; p; p=p->hash_chain) {
p->verify_flag=0;
}
}
}
// Now go through the LRU chain, make sure everything in the LRU chain is hashed, and set the verify flag.
{
PAIR p;
for (p=t->head; p; p=p->next) {
assert(p->verify_flag==0);
PAIR p2;
u_int32_t fullhash = p->fullhash;
//assert(fullhash==toku_cachetable_hash(p->cachefile, p->key));
for (p2=t->table[fullhash&(t->table_size-1)]; p2; p2=p2->hash_chain) {
if (p2==p) {
/* found it */
goto next;
}
}
fprintf(stderr, "Something in the LRU chain is not hashed\n");
assert(0);
next:
p->verify_flag = 1;
}
}
// Now make sure everything in the hash chains has the verify_flag set to 1.
{
u_int32_t i;
for (i=0; i<t->table_size; i++) {
PAIR p;
for (p=t->table[i]; p; p=p->hash_chain) {
assert(p->verify_flag);
}
}
}
cachetable_unlock(t);
}
static void assert_cachefile_is_flushed_and_removed (CACHETABLE t, CACHEFILE cf) {
u_int32_t i;
// Check it two ways
// First way: Look through all the hash chains
for (i=0; i<t->table_size; i++) {
PAIR p;
for (p=t->table[i]; p; p=p->hash_chain) {
assert(p->cachefile!=cf);
}
}
// Second way: Look through the LRU list.
{
PAIR p;
for (p=t->head; p; p=p->next) {
assert(p->cachefile!=cf);
}
}
}
// Write all of the pairs associated with a cachefile to storage. Maybe remove
// these pairs from the cachetable after they have been written.
static int cachefile_write_maybe_remove(CACHETABLE ct, CACHEFILE cf, BOOL do_remove) {
unsigned nfound = 0;
struct writequeue cq;
writequeue_init(&cq);
unsigned i;
for (i=0; i < ct->table_size; i++) {
PAIR p;
for (p = ct->table[i]; p; p = p->hash_chain) {
if (cf == 0 || p->cachefile==cf) {
nfound++;
p->cq = &cq;
if (!p->writing)
flush_and_remove(ct, p, 1);
}
}
}
for (i=0; i<nfound; i++) {
PAIR p = 0;
int r = writequeue_deq(&cq, &ct->mutex, &p); assert(r == 0);
cachetable_complete_write_pair(ct, p, do_remove);
}
writequeue_destroy(&cq);
if (do_remove)
assert_cachefile_is_flushed_and_removed(ct, cf);
if ((4 * ct->n_in_table < ct->table_size) && (ct->table_size>4))
cachetable_rehash(ct, ct->table_size/2);
return 0;
}
/* Require that it all be flushed. */
int toku_cachetable_close (CACHETABLE *tp) {
CACHETABLE t=*tp;
int r;
cachetable_lock(t);
if ((r=cachefile_write_maybe_remove(t, 0, TRUE))) {
cachetable_unlock(t);
return r;
}
u_int32_t i;
for (i=0; i<t->table_size; i++) {
if (t->table[i]) return -1;
}
assert(t->size_writing == 0);
writequeue_set_closed(&t->wq);
cachetable_unlock(t);
threadpool_destroy(&t->threadpool);
writequeue_destroy(&t->wq);
r = toku_pthread_mutex_destroy(&t->mutex); assert(r == 0);
toku_free(t->table);
toku_free(t);
*tp = 0;
return 0;
}
int toku_cachetable_unpin_and_remove (CACHEFILE cachefile, CACHEKEY key) {
int r = ENOENT;
// Removing something already present is OK.
CACHETABLE t = cachefile->cachetable;
PAIR p;
int count = 0;
cachetable_lock(t);
u_int32_t fullhash = toku_cachetable_hash(cachefile, key);
for (p=t->table[fullhash&(t->table_size-1)]; p; p=p->hash_chain) {
count++;
if (p->key.b==key.b && p->cachefile==cachefile) {
p->dirty = 0; // clear the dirty bit. We're just supposed to remove it.
assert(p->rwlock.pinned==1);
ctpair_read_unlock(&p->rwlock);
struct writequeue cq;
writequeue_init(&cq);
p->cq = &cq;
if (!p->writing)
flush_and_remove(t, p, 0);
PAIR pp = 0;
r = writequeue_deq(&cq, &t->mutex, &pp);
assert(r == 0 && pp == p);
cachetable_complete_write_pair(t, p, TRUE);
writequeue_destroy(&cq);
r = 0;
goto done;
}
}
done:
cachetable_unlock(t);
note_hash_count(count);
return r;
}
#if 0
static void flush_and_keep (PAIR flush_me) {
if (flush_me->dirty) {
WHEN_TRACE_CT(printf("%s:%d CT flush_callback(%lld, %p, dirty=1, 0)\n", __FILE__, __LINE__, flush_me->key, flush_me->value));
flush_me->flush_callback(flush_me->cachefile, flush_me->key, flush_me->value, flush_me->size, 1, 1);
flush_me->dirty=0;
}
}
static int cachetable_fsync_pairs (CACHETABLE t, PAIR p) {
if (p) {
int r = cachetable_fsync_pairs(t, p->hash_chain);
if (r!=0) return r;
flush_and_keep(p);
}
return 0;
}
int cachetable_fsync (CACHETABLE t) {
int i;
int r;
for (i=0; i<t->table_size; i++) {
r=cachetable_fsync_pairs(t, t->table[i]);
if (r!=0) return r;
}
return 0;
}
#endif
#if 0
int cachefile_pwrite (CACHEFILE cf, const void *buf, size_t count, toku_off_t offset) {
ssize_t r = pwrite(cf->fd, buf, count, offset);
if (r==-1) return errno;
assert((size_t)r==count);
return 0;
}
int cachefile_pread (CACHEFILE cf, void *buf, size_t count, toku_off_t offset) {
ssize_t r = pread(cf->fd, buf, count, offset);
if (r==-1) return errno;
if (r==0) return -1; /* No error for EOF ??? */
assert((size_t)r==count);
return 0;
}
#endif
int toku_cachetable_checkpoint (CACHETABLE ct) {
// Requires: Everything is unpinned. (In the multithreaded version we have to wait for things to get unpinned and then
// grab them (or else the unpinner has to do something.)
// Algorithm: Write a checkpoint record to the log, noting the LSN of that record.
// Note the LSN of the previous checkpoint (stored in lsn_of_checkpoint)
// For every (unpinnned) dirty node in which the LSN is newer than the prev checkpoint LSN:
// flush the node (giving it a new nodeid, and fixing up the downpointer in the parent)
// Watch out since evicting the node modifies the hash table.
//?? This is a skeleton. It compiles, but doesn't do anything reasonable yet.
//?? log_the_checkpoint();
struct writequeue cq;
writequeue_init(&cq);
cachetable_lock(ct);
// set the checkpoint in progress flag. if already set then just return.
if (!ct->checkpointing) {
ct->checkpointing = 1;
unsigned nfound = 0;
unsigned i;
for (i=0; i < ct->table_size; i++) {
PAIR p;
for (p = ct->table[i]; p; p=p->hash_chain) {
// p->dirty && p->modified_lsn.lsn>ct->lsn_of_checkpoint.lsn
if (1) {
nfound++;
p->cq = &cq;
if (!p->writing)
flush_and_remove(ct, p, 1);
}
}
}
for (i=0; i<nfound; i++) {
PAIR p = 0;
int r = writequeue_deq(&cq, &ct->mutex, &p); assert(r == 0);
cachetable_complete_write_pair(ct, p, FALSE);
}
{
CACHEFILE cf;
for (cf = ct->cachefiles; cf; cf=cf->next) {
if (cf->checkpoint_userdata) {
int r = cf->checkpoint_userdata(cf, cf->userdata);
assert(r==0);
}
}
}
ct->checkpointing = 0; // clear the checkpoint in progress flag
}
cachetable_unlock(ct);
writequeue_destroy(&cq);
return 0;
}
TOKULOGGER toku_cachefile_logger (CACHEFILE cf) {
return cf->cachetable->logger;
}
FILENUM toku_cachefile_filenum (CACHEFILE cf) {
return cf->filenum;
}
#if DO_WRITER_THREAD
// The writer thread waits for work in the write queue and writes the pair
static void *cachetable_writer(void *arg) {
// printf("%lu:%s:start %p\n", toku_pthread_self(), __FUNCTION__, arg);
CACHETABLE ct = arg;
int r;
cachetable_lock(ct);
while (1) {
threadpool_set_thread_idle(ct->threadpool);
PAIR p = 0;
r = writequeue_deq(&ct->wq, &ct->mutex, &p);
if (r != 0)
break;
threadpool_set_thread_busy(ct->threadpool);
cachetable_write_pair(ct, p);
}
cachetable_unlock(ct);
// printf("%lu:%s:exit %p\n", toku_pthread_self(), __FUNCTION__, arg);
return arg;
}
#endif
// debug functions
int toku_cachetable_assert_all_unpinned (CACHETABLE t) {
u_int32_t i;
int some_pinned=0;
cachetable_lock(t);
for (i=0; i<t->table_size; i++) {
PAIR p;
for (p=t->table[i]; p; p=p->hash_chain) {
assert(ctpair_pinned(&p->rwlock)>=0);
if (ctpair_pinned(&p->rwlock)) {
//printf("%s:%d pinned: %"PRId64" (%p)\n", __FILE__, __LINE__, p->key.b, p->value);
some_pinned=1;
}
}
}
cachetable_unlock(t);
return some_pinned;
}
int toku_cachefile_count_pinned (CACHEFILE cf, int print_them) {
u_int32_t i;
int n_pinned=0;
CACHETABLE t = cf->cachetable;
cachetable_lock(t);
for (i=0; i<t->table_size; i++) {
PAIR p;
for (p=t->table[i]; p; p=p->hash_chain) {
assert(ctpair_pinned(&p->rwlock)>=0);
if (ctpair_pinned(&p->rwlock) && (cf==0 || p->cachefile==cf)) {
if (print_them) printf("%s:%d pinned: %"PRId64" (%p)\n", __FILE__, __LINE__, p->key.b, p->value);
n_pinned++;
}
}
}
cachetable_unlock(t);
return n_pinned;
}
void toku_cachetable_print_state (CACHETABLE ct) {
u_int32_t i;
cachetable_lock(ct);
for (i=0; i<ct->table_size; i++) {
PAIR p = ct->table[i];
if (p != 0) {
printf("t[%u]=", i);
for (p=ct->table[i]; p; p=p->hash_chain) {
printf(" {%"PRId64", %p, dirty=%d, pin=%d, size=%ld}", p->key.b, p->cachefile, p->dirty, p->rwlock.pinned, p->size);
}
printf("\n");
}
}
cachetable_unlock(ct);
}
void toku_cachetable_get_state (CACHETABLE ct, int *num_entries_ptr, int *hash_size_ptr, long *size_current_ptr, long *size_limit_ptr) {
cachetable_lock(ct);
if (num_entries_ptr)
*num_entries_ptr = ct->n_in_table;
if (hash_size_ptr)
*hash_size_ptr = ct->table_size;
if (size_current_ptr)
*size_current_ptr = ct->size_current;
if (size_limit_ptr)
*size_limit_ptr = ct->size_limit;
cachetable_unlock(ct);
}
int toku_cachetable_get_key_state (CACHETABLE ct, CACHEKEY key, CACHEFILE cf, void **value_ptr,
int *dirty_ptr, long long *pin_ptr, long *size_ptr) {
PAIR p;
int count = 0;
int r = -1;
u_int32_t fullhash = toku_cachetable_hash(cf, key);
cachetable_lock(ct);
for (p = ct->table[fullhash&(ct->table_size-1)]; p; p = p->hash_chain) {
count++;
if (p->key.b == key.b && p->cachefile == cf) {
note_hash_count(count);
if (value_ptr)
*value_ptr = p->value;
if (dirty_ptr)
*dirty_ptr = p->dirty;
if (pin_ptr)
*pin_ptr = p->rwlock.pinned;
if (size_ptr)
*size_ptr = p->size;
r = 0;
break;
}
}
cachetable_unlock(ct);
note_hash_count(count);
return r;
}
void
toku_cachefile_set_userdata (CACHEFILE cf,
void *userdata,
int (*close_userdata)(CACHEFILE, void*),
int (*checkpoint_userdata)(CACHEFILE, void*))
{
cf->userdata = userdata;
cf->close_userdata = close_userdata;
cf->checkpoint_userdata = checkpoint_userdata;
}
void *toku_cachefile_get_userdata(CACHEFILE cf) {
return cf->userdata;
}
int toku_cachefile_redirect_nullfd (CACHEFILE cf) {
int null_fd;
struct fileid fileid;
null_fd = open(DEV_NULL_FILE, O_WRONLY+O_BINARY);
assert(null_fd>=0);
toku_os_get_unique_file_id(null_fd, &fileid);
close(cf->fd);
cf->fd = null_fd;
if (cf->fname) {
toku_free(cf->fname);
cf->fname = 0;
}
cachefile_init_filenum(cf, null_fd, NULL, fileid);
return 0;
}